The long-lived Mars rover Opportunity has spotted bright veins of a water-deposited mineral, apparently gypsum, on the surface of the planet. The vein is informally named 'Homestake,' and it and other similar-looking deposits are located in a zone where sulfate-rich bedrock meets volcanic bedrock, at the rim of the Endeavour Crater. Homestake is roughly 0.4 to 0.8 inches wide, 16 to 20 inches long, and protrudes slightly above the surrounding bedrock.

The Homestake vein likely formed as calcium, dissolved by water out of volcanic rocks, combined with sulfur and was deposited as calcium sulfate in an underground fracture, which was then exposed at the surface of Mars.

Steve Squyres, principal investigator for Opportunity, said in a statement: "This tells a slam-dunk story that water flowed through underground fractures in the rock. This stuff is a fairly pure chemical deposit that formed in place right where we see it. That can't be said for other gypsum seen on Mars or for other water-related minerals Opportunity has found. It's not uncommon on Earth, but on Mars, it's the kind of thing that makes geologists jump out of their chairs."

Opportunity has found other evidence of water on Mars in the form of magnesium, iron and calcium sulfate in the bedrock, but that same evidence has also indicated a highly acidic environment. This new deposit indicates more neutral conditions, which could have hosted a greater variety of organisms.

"This image, taken December 6, 2011, combines two separate views of the giant asteroid Vesta obtained by NASA's Dawn spacecraft. The images were taken by Dawn's framing camera. The far-left image uses near-infrared filters where red is used to represent 750 nanometers, green represents 920 nanometers and blue represents 980 nanometers. The image on the right is an image with colors assigned by scientists, representing different rock or mineral types on Vesta, revealing a world of many varied, well-separated layers and ingredients.

The fresh impact craters in this view are located in the south polar region, which has been partly covered by landslides from the adjacent crater. This would suggest that a layer of loose material covers the Vesta surface."

On December 8, 2010, SpaceX successfully completed a demonstration flight for NASA's Commercial Orbital Transportation Services (COTS) program with the flight of the first Falcon9 carrying a Dragon capsule.

The Dragon capsule completed two orbits and splashed down safely in the Pacific Ocean, making SpaceX the first commercial company to successfully launch and retrieve a capsule from low-Earth orbit.

SpaceX later revealed that Dragon carried a secret payload: a wheel of cheese.

Editor's note: Lisa Randall is Frank B. Baird Jr. Professor of Science at Harvard University. A physicist, Randall is the author of "Knocking on Heaven's Door." She was among Time Magazine's "100 Most Influential People" of 2007.

(CNN) - On a recent visit to Barcelona, Spain, my local translator, who told me he was becoming increasingly interested in physics as he listened to my responses to reporters' questions, commented that he couldn't believe the biggest advances in my field will come not from America but from Europe - for him, an unexpected turn.

The Large Hadron Collider, the enormous machine that collides protons to study matter at higher energies and shorter distances than ever is in Europe (near Geneva, Switzerland) and not in America, where most important particle physics discoveries have taken place in the past. The European community has remained steadfastly supportive of this international enterprise and, unlike America of late, recognizes the importance of maintaining its scientific commitments.

If current political discussions are any indication, America is in danger not only of losing scientific leadership but also of losing respect for the scientific method itself. This is at a time when the type of clear and rational thinking that science teaches us is more relevant than ever. Given the challenging problems we face today, our country needs to embrace the scientific values that have served us so well.

Much of our economy, from the ever-tinier and more powerful products of our electronics industry to the most cost-effective manufacturing processes to the latest marketing and advertising tactics, has emerged from scientific advances and reasoning. So have many sensible government policies and programs, even if they are often also politically compromised.

Science features prominently in many current debates, including those over climate change, searches for alternative energy sources and progress in medical care. But other issues that aren't strictly scientific also involve the big numbers and complicated interwoven decisions for which scientific thinking can help. Yes science is difficult and some people feel disempowered by how much we need to understand. But so are such challenges as establishing stability in the Middle East, fixing the economy, restoring job growth and ensuring financial stability.

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